There’s a Chick-fil-A across the street from my office in Lehi that I sometimes go to. (I love their breakfast muffins.) Unfortunately, there’s a problem.

To showcase this problem, I pulled up this satellite picture of the situation. (It’s outdated, so I added a picture where Chick-fil-A is.) The blue arrows show how I turn from the highway into the road where Chick-fil-A (and my work) is.

Now, here’s the kicker. There are two roads you can use to get into this area. The road closest to Chick-fil-A, the road most natural to turn into, has a strange innovation: a triangle structure, which encourages cars only to turn in when driving north-from-south (in this picture, driving upwards toward the highway). So basically, if I’m coming on the blue arrows (from the north), they’re saying: take the next road, the green road. It’s longer, but the entrance is safer.

Here’s the thing. Ain’t nobody got time for that. People end up doing this:

Which is, mind you, unsafe–both to the drivers and to the pedestrians, because pedestrians aren’t expecting to have to look out for cars coming in this way, and because if the car has to stop for any reason, they’re in the line of traffic.

But here’s the thing: it’s also entirely natural–and it’s used more often than the “safe” (green) path. When I’m in the car, I expect to be able to take a left into that road. The triangle thing is so unnatural, even though it was probably built because the middle turn lane wasn’t long enough at that point. So it makes sense, perhaps, from a road design perspective; but it doesn’t make sense from what drivers expect.

This is an example, I’ve learned, of something called a desire line. I first read about these in the book Universal Principles of Design, where is says this:

Desire lines generally refer to to worn paths where people naturally walk–the beaten path that trails off the sidewalk, usually as a shortcut to a destination–but can be applied more broadly to any signs or traces of user activity in an object or environment. The implicit claim of desire lines is that they represent an unbiased indication of how an object or environment is actually used by people…

Wikipedia also adds some fun synonyms: “game trail, social trail, herd path, cow path, goat track, pig trail, use trail or bootleg trail.” I’ve also seen them called elephant tracks or “pedestrian’s revenge” (which wins for being the most memorable, I think). Again: they’re just the unpaved paths that develop based on animal and human traffic. If you google “desire lines,” you get pictures like this:

Which I think relates back to the Chick-fil-A example perfectly.

The obvious design implication for Chick-fil-A (and whoever owns or manages the property) is that this desire line, this evidence of human activity, is the preferred path. This is important–all the more so because this behavior has lots of implications for the safety of drivers and pedestrians alike.

The implications for designers generally is this: consider how users actually use your products. For interface design, this can be discovered through analytics, heat maps, and good old user testing. Where do people using the product stumble? How do they behave? Are there instances where they try to take a shortcut, using the product in an unintended way?

Something to think about. In the meantime, be careful when driving to Chick-fil-A!